Bottom Line:
Based on analysis with pulsed field gel electrophoresis, END-49 was found to consist of five genomically distinct bacterial lineages, designated Group I-V, with Group I strains dominating the culture.Genomic analysis is under way to identify all members in END-49 involved in the biotransformation and the actual pathway leading to END-production.Biotransformation is a very economic, efficient and environmentally friendly way of mass-producing enterodiol from defatted flaxseeds.

Background: The effects of enterolignans, e.g., enterodiol (END) and particularly its oxidation product, enterolactone (ENL), on prevention of hormone-dependent diseases, such as osteoporosis, cardiovascular diseases, hyperlipemia, breast cancer, colon cancer, prostate cancer and menopausal syndrome, have attracted much attention. To date, the main way to obtain END and ENL is chemical synthesis, which is expensive and inevitably leads to environmental pollution. To explore a more economic and eco-friendly production method, we explored biotransformation of enterolignans from precursors contained in defatted flaxseeds by human intestinal bacteria.

Results: We cultured fecal specimens from healthy young adults in media containing defatted flaxseeds and detected END from the culture supernatant. Following selection through successive subcultures of the fecal microbiota with defatted flaxseeds as the only carbon source, we obtained a bacterial consortium, designated as END-49, which contained the smallest number of bacterial types still capable of metabolizing defatted flaxseeds to produce END. Based on analysis with pulsed field gel electrophoresis, END-49 was found to consist of five genomically distinct bacterial lineages, designated Group I-V, with Group I strains dominating the culture. None of the individual Group I-V strains produced END, demonstrating that the biotransformation of substrates in defatted flaxseeds into END is a joint work by different members of the END-49 bacterial consortium. Interestingly, Group I strains produced secoisolariciresinol, an important intermediate of END production; 16S rRNA analysis of one Group I strain established its close relatedness with Klebsiella. Genomic analysis is under way to identify all members in END-49 involved in the biotransformation and the actual pathway leading to END-production.

Conclusion: Biotransformation is a very economic, efficient and environmentally friendly way of mass-producing enterodiol from defatted flaxseeds.

Figure 2: END production curve in medium A and medium B. Each data point represents the mean of at least 2 independent determinations. No END was detected in medium C.

Mentions:
When the cultures were terminated, END could be detected in media A and B, but not C, with the yield of END in medium B being considerably higher than that in medium A (Fig. 2). These results indicated that a nitrogen source (NH4Cl in this study, present in B but not in C) was necessary to support the bacteria that could transform flaxseed lignans into END. Based on these results, we chose medium B for bacterial cultures.

Figure 2: END production curve in medium A and medium B. Each data point represents the mean of at least 2 independent determinations. No END was detected in medium C.

Mentions:
When the cultures were terminated, END could be detected in media A and B, but not C, with the yield of END in medium B being considerably higher than that in medium A (Fig. 2). These results indicated that a nitrogen source (NH4Cl in this study, present in B but not in C) was necessary to support the bacteria that could transform flaxseed lignans into END. Based on these results, we chose medium B for bacterial cultures.

Bottom Line:
Based on analysis with pulsed field gel electrophoresis, END-49 was found to consist of five genomically distinct bacterial lineages, designated Group I-V, with Group I strains dominating the culture.Genomic analysis is under way to identify all members in END-49 involved in the biotransformation and the actual pathway leading to END-production.Biotransformation is a very economic, efficient and environmentally friendly way of mass-producing enterodiol from defatted flaxseeds.

Background: The effects of enterolignans, e.g., enterodiol (END) and particularly its oxidation product, enterolactone (ENL), on prevention of hormone-dependent diseases, such as osteoporosis, cardiovascular diseases, hyperlipemia, breast cancer, colon cancer, prostate cancer and menopausal syndrome, have attracted much attention. To date, the main way to obtain END and ENL is chemical synthesis, which is expensive and inevitably leads to environmental pollution. To explore a more economic and eco-friendly production method, we explored biotransformation of enterolignans from precursors contained in defatted flaxseeds by human intestinal bacteria.

Results: We cultured fecal specimens from healthy young adults in media containing defatted flaxseeds and detected END from the culture supernatant. Following selection through successive subcultures of the fecal microbiota with defatted flaxseeds as the only carbon source, we obtained a bacterial consortium, designated as END-49, which contained the smallest number of bacterial types still capable of metabolizing defatted flaxseeds to produce END. Based on analysis with pulsed field gel electrophoresis, END-49 was found to consist of five genomically distinct bacterial lineages, designated Group I-V, with Group I strains dominating the culture. None of the individual Group I-V strains produced END, demonstrating that the biotransformation of substrates in defatted flaxseeds into END is a joint work by different members of the END-49 bacterial consortium. Interestingly, Group I strains produced secoisolariciresinol, an important intermediate of END production; 16S rRNA analysis of one Group I strain established its close relatedness with Klebsiella. Genomic analysis is under way to identify all members in END-49 involved in the biotransformation and the actual pathway leading to END-production.

Conclusion: Biotransformation is a very economic, efficient and environmentally friendly way of mass-producing enterodiol from defatted flaxseeds.